A major route for the transport of chemical contaminants from the environment to man is through the ingestion of contaminated fish and shellfish. Assessment of the impact of superfund chemicals on the human population requires accurate predictions of the extent to which aquatic organisms may accumulate chemicals. Existing models do not adequately account for bioconcentration, bioaccumulation and kinetics when describing the transport of chemicals form water, suspended particulates and food to fish. We have previously fund that food chain transport of contaminants in aquatic systems depends upon pharmacokinetic considerations; existing models to predict chemical burdens in fish can be improved including pharmacokinetic data. The objectives of this project are to determine rates of bioconcentration of Cd, MeHg, PCBs and BaP in fish (striped bass), and to ascertain the extent to which bioconcentration is modified by the presence of particulate matter suspended in water. We will also determine the relative importance of bioconcentration from water compared to accumulation of chemicals through the food chain. Bioconcentration and bioaccumulation of chemicals will be determined from experiments in which fish are dosed with radiolabeled chemicals for fixed periods of time. Juvenile striped bass will be exposed to chemicals dissolved in water, adsorbed to suspended particulate matter, or present in the food. Studies of uptake from water and particulate matter will use a "flow- through" bioassay system. Studies of uptake from food will be determined in both single-dose and multiple-dose studies. Assimilation, tissue distribution and elimination of the individual chemicals from fish will be determined for different doses and different salinities over periods ranging from 10 days to 20 days. The data from studies of uptake and elimination will be applied in the development of pharmacokinetic models useful in predicting body burdens of contaminants likely to be accumulated by striped bass under conditions where the availability of the chemical contaminant may be controlled by physical and biological factors.